> Why assume something is a “small” part necessarily would result in a repair price that is less than x% of purchase price?

It's not a mere assumption. There do exist people who do many repairs better than Apple for hundreds of dollars less, in the US.

That is not related to the quoted statement.

As a hypothetical, suppose the camera glass or lens was made with materials or a technique that caused it to be 90% of a phone’s cost to produce. Then replacing this item would cost >90% of the phone’s price, even though it is “small”.

Or you have a huge transport ship that has an issue with a propeller or a small part of the ship on the bottom, but it needs a dry dock to repair, and there are only a couple dry docks in the world that can handle it. Then the price could be a very high percentage of original price due to the extreme supply and demand curves involved.

Repair costs are not a simple a function of the “size” of the damage.

> As a hypothetical, suppose the camera glass or lens was made with materials or a technique that caused it to be 90% of a phone’s cost to produce. Then replacing this item would cost >90% of the phone’s price, even though it is “small”.

When I say there are people who do the repair for much cheaper I mean including the price they pay for the part, not merely their labor. Your hypothetical is not the case here.

I addressed that with this portion of the original comment :

>Of course, the ability for only one entity to source and supply those will tilt the scales towards a higher price

I don't get how that addresses anything. Maybe they're "tilted" toward a "higher" price, but until you put actual numbers on these (are we talking $10 higher or $1000 higher?) it doesn't say anything. I'm saying that, for a wide variety of common repairs, it is a fact that you can literally get the exact same repair done for the exact same issue (parts, labor, everything being the same) for far less (literally hundreds) than Apple does it for you. And I'm talking about profitable businesses here, not charities. There's no need to give hypothetical academic rebuttals on economics when the facts are clear on the ground.

The only thing broken on the Mac was the glass display, which I guarantee you does not cost more than $100 to replace wholesale, even with labor. However, Apple doesn't offer this repair for you. Instead, they sell you an entire topcase to replace the entire top half of your computer, even if your aluminum case, display, hinge, backlight, microphone and webcam are all fine. Your only option is replacing everything, at which point, I think OP has reason to be mad. Apple simply doesn't invest money in making their devices more repairable, they make too much money off selling replacements for it to be lucrative. That's fine, and their decision to make, but there's a real human/UX cost that comes with making fragile hardware.

No that’s ridiculous. These retina displays go for $400 on eBay (for a used one) and labor isn’t going to be less than $100 on top of that.

Parts? Manufacturing? Shipping? Labour? Storage? Distribution? There's more to a part than the cost. Now whether or not what they're charging is over the top, then I doubt you'll find much disagreement; however, the GP doesn't say how the damage happened. I don't know of a single vendor that will cover accidental damages on a screen, and no-one is responsible other than the party that caused the damage. Also, late 2020 MBA (M1) goes for $465, with ~$30 for the parts, ~$15 for shipping.

Edited words...